The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 26, 2004
Filed:
Dec. 10, 2002
Applicant:
Inventor:
Tetsuya Shimoda, Tokyo, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03L 7/085 ; H03L 7/087 ; G09G 5/00 ;
U.S. Cl.
CPC ...
H03L 7/085 ; H03L 7/087 ; G09G 5/00 ;
Abstract
In a phase locked loop (PLL) circuit having a function of automatically adjusting the free-running frequency of a voltage controlled oscillator (VCO), the number of pulses of a pulse signal output from the VCO in a period in which a comparison signal output from a phase comparator is at a predetermined level is counted, and a microcomputer updates digital data based on the counted value. The digital data is converted into an analog signal by a digital-to-analog converter. A combiner combines the analog signal with a signal obtained by smoothing the comparison signal of the phase comparator by a low-pass filter so as to generate a frequency control signal of the VCO.